Dr Richa Sharma, Dr Amit Basnotra
Pregnancy whether nature or IVF comes with a great news in family and all await till nine months for a healthy baby to be born and fill happiness.Sad part when after nine months of efforts one may unfortunately have a baby born with some abnormalities or disabilities.Science is making a continous efforts to avoid such mishaps to happen and knock door of anyone.There are few old crude ways to rule out any such possibility before hand only but that puts baby in womb at risk with posiibility of harm to carrying mom also.So definitely as patients one like to be aware of whats best and safe.
Via this write up we want to focus on latest in talk and most non invasive modality to know your baby’s risk to have abnormalities post birth.This latest single and simple blood test makes genetic screening more reliable
Various random terms often heard via google or via your Doctor like-
* Invasive and Non Invasive Methods
* Preconceptional,Prenatal and Antenatal Methods
* NIPT * PGD/PGS
What they all upto,lets discuss that !!
DNA Of Baby and Parents-
Besides knowing DNA of parents by Karyotyping,you may be surprised to know that your blood carries baby’s DNA(cell free DNA or cfDNA) too so that actually forms the basis of all these novel tests.
Prenatal diagnostic testing-
It involves testing the fetus before birth to determine whether the fetus has certain abnormalities,more so especially if female falls into advanced age group .There are a variety of non-invasive and invasive techniques available for prenatal diagnosis. Each of them can be applied only during specific time periods during the pregnancy for greatest utility. The techniques employed for prenatal diagnosis include:
* Ultrasonography
* Amniocentesis
* Chorionic villus sampling
* Fetal Blood Sampling
* Genetic Sonogram
Pre-implantation genetic diagnosis (PGD)-
Its done in cases of IVF (in vitro fertilization) who are at increased risk of having a baby with a genetic or chromosomal disorder. Before an embryo is transferred to a woman’s uterus, it is tested for certain genetic disorders and mutations. Only embryos that do not test positive for the disorders are transferred.
Screening During pregnancy-
Women are customarily offered a variety of genetic screening tests during their first/second trimester of pregnancy to evaluate the risk for genetic disorders for their unborn baby. Information from these screening tests are used to help determine even the slightest possibility that the fetus might be born with genetic disorders such as Down syndrome, cystic fibrosis, Tay-Sachs disease, sickle cell anaemia, etc.
NIPT(Non Invasive prenatal test)-
It checks for DNA of your baby’s placenta in your blood sample.It can check for likelihood of having an abnormal baby with accuracy of 99% so that you and your doctor can decide for next steps.Purpose is to avoid risk of miscarriage associated with the invaise methods like-Chorionic villous sampling(cvs) and amniocentesis.
Safety -This test is simple, quick and safe
Interpretation- Once the results come then your doctor will correlate with first trimester soft tissue markers via screening
Diseases screened-
* Various common chromosomal disorders are detected like- Downs syndrome,Edwards syndrome and Patau syndrome, even triploidies, microdeletions
* Blood group and Rh factor of baby
* Sex of baby (Purpose is not gender determination as that’s Illegal and punishable in India to ask or to suggest both under PCPNDT act.Aim as certain genetic diseases run in certain families in particular gender only so that if same recurs timely call can be taken)
Time zone to do test-
Well NIPT though non invasive but still its time duration to do can vary as per country as per law of termination of pregnancy.Also authentication of that lab is a must.It means that particular IVF or High risk obstetrics centre you seeking help should be authorized to do so from related authorities.There can be variation as per state to state even.
In India, NIPT can be done 9 weeks onwards
Who all should do NIPT ?(Indications)
* Maternal age > 35 years
* Family history of anomalies
* Previous baby born with anomalies
* Recurrent miscarriages
What does latest guidelines say ?
Though there are a set of indications but still latest guidelines suggest it to be offered to all pregnant mothers irrespective of age.Rather if clinic can afford should empanel an independent genetic counselor.Its a cafeteria choice for couples but definitely as doctor we should give them complete information so that an intelligent informed decision can be taken at the end
(All information shared is as per clinical and evidence based and authors in good faith donot suggest to follow it blindly.Its for awareness of our Jammuities Seek help of your doctor before taking any decision)
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